What kind of metal is used for the GMC frame?
Frame: Ladder type welded frame with 6 x 2.50 x .125 channel SAE 950 side rails and SAE 1023 channel cross-members. (1973 GMC brochure) The first number designates the type of steel. 10 being plain carbon steel 2 nickel steels, 3 nickel chromium steels etc, the 9 being silcon manganese steel I believe. The second number indicates the approximate amount of the predominant alloy, the last 2 or 3 numbers designates the carbon content. So my understanding is that SAE 1023 is plain carbon steel, and .23% carbon. In other words any steel will do for cross members. I’ll have to go to the library and get a American Iron and Steel Institute book to decode the SAE 950. (Tom Warner 12-28-99) SAE 950 is a high strength, low allow steel. Here are some details: This type of steel has enhanced mechanical properties and, in most cases, good resistance to atmospheric corrosion are obtained by the addition of moderate amounts of one or more alloying elements other than carbon. Steels of this type are no
